Complete rewrite of triangulation engine:
- Regular hexagonal-packed vertex grid (equilateral triangles)
- Density-adaptive refinement: denser near holes, coarser in open areas
- Boundary-conforming vertices along frame edge and hole keepouts
- Delaunay on point set + clip to valid region (inside frame, outside keepouts)
- Result: proper isogrid layout, 87 pockets from 234 triangles
- 553 NX entities, min fillet 4.89mm, mass 2770g
- No more dependency on Shewchuk Triangle library (scipy.spatial.Delaunay)
- Switched to uniform triangulation (no density-adaptive refinement for
initial pass — saves that for stress-informed iterations)
- s_min=45mm, s_max=55mm (was 12/35) — larger triangles fit 6mm fillets
- Boss keepout circles: 12 segments (was 32) — less boundary clutter
- Fillet must be >= 80% of r_f at every corner or pocket is skipped
- Result: 75 pockets, 481 NX entities, min fillet 4.85mm, mass 4066g
- adaptive_density=True param enables density refinement for future stress iterations
